<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }
      .flex-box {
        width: 500px;
        height: 200px;
        background-color: #ff0;
        display: flex;
        /* margin: 0 auto; */
      }
      .flex-item {
        width: 100px;
        height: 100px;
        background-color: #0ff;
      }
      .flex-item:nth-of-type(2) {
        /* margin-right: auto; */
        /* float: left; */
        /* position: relative; */
      }
    </style>
  </head>
  <body>
    <div class="flex-box">
      <div class="flex-item">1</div>
      <div class="flex-item">2</div>
      <div class="flex-item">3</div>
      <div class="flex-item">1</div>
      <div class="flex-item">2</div>
      <div class="flex-item">3</div>
    </div>
  </body>
</html>

